External fixation devices are used to stabilize bone segments and to facilitate the healing of bones at a bone repair site. As used herein “bone repair site” refers to any bone region which is bounded on at least one side by a relatively healthy bone region to which orthopedic devices can be secured, such as an osteotomy defect or a fracture. Distraction and reduction/compression devices may be incorporated into an external fixation device and may be used to gradually adjust the relative orientation and spacing of the bone parts on opposing sides of a bone repair site.
External fixation devices traditionally include a bar(s), rod(s) and/or arcuate ring(s) as well as transcutaneous pins, screws and/or wires, which are inserted into bone on either side of the bone repair site. Clamps are used to attach the pins, screws and/or wires to the bar(s), rod(s) and/or arcuate ring(s). These clamps may be used to adjust the relative positions of the pins, screws or wires relative to each other as well as the bar(s), rod(s) and/or arcuate ring(s) so that bone segments may be aligned at the bone repair site. When the desired alignment is achieved, the clamps are locked in place to maintain the alignment of bone segments.
Distraction and reduction/compression devices may allow for adjustment of the distance between components attached on opposing sides of a bone repair site. A typical distraction procedure involves at most an osteotomy completely separating the bone into two segments, or at least an incision of the cortical portion of the bone. A distraction device moves components of the fixation device in order to gradually separate the bone segments on either side of the osteotomy (or the medullary or cancellous portion of the bone on either side of the incision). This gradual separation allows new bone to form in the osteotomy void. In other cases, reduction or compression across a bone repair site to hold bone portions together is desired to facilitate healing. Such adjustments, whether distraction or reduction/compression, typically follow a prescribed protocol. After each adjustment, the distraction/reduction/compression device is held fixed and the new bone growth gains strength. After the bone repair site has healed, the external fixation device is removed from the patient.
Existing distraction/reduction/compression devices employ adjustment mechanisms which may be awkward, slow and difficult to adjust in an incremental and reliable fashion. For example, hex nuts or similar conventional fasteners engaged with a threaded bolt or rod are often used to secure components of an external fixation device. These fasteners are assembled and adjusted using a wrench or other tool. Patients and their non-physician caregivers are often tasked with adjusting an external fixation device according to a specific treatment protocol. However, the complexity of existing systems can often lead to improper adjustments, non-compliance or deviation from the prescribed protocol, and/or undue discomfort for the patient.
Accordingly, it is desirable to provide external fixation devices, methods and kits having improved distraction and connection assemblies for stabilizing bone segments and for providing simple and reliable incremental adjustments.